docs: def _task_complete(self, **kwargs):
          """ Performs cleanup tasks and notifies Job that the Task finished. """
          logger.debug('Running _task_complete for task {0}'.format(self.name))
          with self.parent_job.completion_lock:
              self.completed_at = datetime.utcnow()
              self.successful = kwargs.get('success', None)
              self.parent_job._complete_task(self.name, **kwargs)